Grind the French-fried onions up in a food processor until smooth.
Beat the egg in a shallow dish or pie pan while you heat the oil in a frying pan.
Sprinkle the fish with salt, dip in the egg and then the onion crumbs. Fry about 2 minutes per side, until done. (The fish will flake apart with a fork easily.)
Serve with lemon wedges and/or a bit of tartar sauce.